Detailed explanation of examples of PHP bit operator permission operations

Regarding the bit operations of binary numbers, the three most common operations are "OR, AND, NOT". Of course, PHP Manual also has "XOR, These three operations are "left shift and right shift".

How to define permissions
Define the value of permissions according to 2 to the Nth power, and so on. Why define it this way? This definition ensures that there is only one 1 in each permission value (binary), and it corresponds to exactly one permission. For example:

define('ADD', 1); // 增加权限
define('UPD', 2); // 修改权限
define('SEL', 4); // 查找权限
define('DEL', 8); // 删除权限

Permission operation
Permission operation actually involves the concept of "role". Performing permission operations is nothing more than granting certain permissions to a certain role, prohibiting certain permissions, and detecting whether a certain role has certain permissions. Relative to these three operations. It can be easily implemented using arithmetic operations between binary numbers.

// 给予某种权限用到“位或”运算符
$a_access = ADD | UPD | SEL | DEL; // a拥有增删改查权限
$b_access = ADD | UPD | SEL; // b拥有增改查权限
$c_access = ADD | UPD; // c拥有增改权限
// 禁止某种权限用“位与”和“位非”运算符
$d_access = $c_access & ~UPD; // d只拥有了增权限
// 检测是否拥有某种权限用到“位与”运算符
var_dump($b_access & ADD); // 1代表b拥有增权限
var_dump($b_access & DEL); // 0代表b不拥有删权限

Implementing simple permission classes and role classes
Using the above permission operation method, it can be simply encapsulated into a permission class and a role class.

<?php
/**
 * 简单权限类
 */
class Peak_Auth {
    /**
     * 权限类计数器
     * 作用在于生成权限值
     *
     * @var int
     */
    protected static $authCount = 0;
    /**
     * 权限名称
     *
     * @var string
     */
    protected $authName;
    /**
     * 权限详细信息
     *
     * @var string
     */
    protected $authMessage;
    /**
     * 权限值
     *
     * @var int 2的N次方
     */
    protected $authValue;
    /**
     * 构造函数
     * 初始化权限名称、权限详细信息以及权限值
     *
     * @param string $authName 权限名称
     * @param string $authMessage 权限详细信息
     */
    public function construct($authName, $authMessage = &#39;&#39;) {
        $this->authName = $authName;
        $this->authMessage = $authMessage;
        $this->authValue = 1 << self::$authCount;
        self::$authCount++;
    }
    /**
     * 本类不允许对象复制操作
     */
    private function clone() {
    }
    /**
     * 设置权限详细信息
     *
     * @param string $authMessage
     */
    public function setAuthMessage($authMessage) {
        $this->authMessage = $authMessage;
    }
    /**
     * 获取权限名称
     *
     * @return string
     */
    public function getAuthName() {
        return $this->authName;
    }
    /**
     * 获取权限值
     *
     * @return int
     */
    public function getAuthValue() {
        return $this->authValue;
    }
    /**
     * 获取权限详细信息
     *
     * @return string
     */
    public function getAuthMessage() {
        return $this->authMessage;
    }
}
/**
 * 简单角色类
 *
 * @author 27_Man
 */
class Peak_Role {
    /**
     * 角色名
     *
     * @var string
     */
    protected $roleName;
    /**
     * 角色拥有的权限值
     *
     * @var int
     */
    protected $authValue;
    /**
     * 父角色对象
     *
     * @var Peak_Role
     */
    protected $parentRole;
    /**
     * 构造函数
     *
     * @param string $roleName 角色名
     * @param Peak_Role $parentRole 父角色对象
     */
    public function construct($roleName, Peak_Role $parentRole = null) {
        $this->roleName = $roleName;
        $this->authValue = 0;
        if ($parentRole) {
            $this->parentRole = $parentRole;
            $this->authValue = $parentRole->getAuthValue();
        }
    }
    /**
     * 获取父角色的权限
     */
    protected function fetchParenAuthValue() {
        if ($this->parentRole) {
            $this->authValue |= $this->parentRole->getAuthValue();
        }
    }
    /**
     * 给予某种权限
     *
     * @param Peak_Auth $auth
     * @return Peak_Role 以便链式操作
     */
    public function allow(Peak_Auth $auth) {
        $this->fetchParenAuthValue();
        $this->authValue |=  $auth->getAuthValue();
        return $this;
    }
    /**
     * 阻止某种权限
     *
     * @param Peak_Auth $auth
     * @return Peak_Role 以便链式操作
     */
    public function deny(Peak_Auth $auth) {
        $this->fetchParenAuthValue();
        $this->authValue &= ~$auth->getAuthValue();
        return $this;
    }
    /**
     * 检测是否拥有某种权限
     *
     * @param Peak_Auth $auth
     * @return boolean
     */
    public function checkAuth(Peak_Auth $auth) {
        return $this->authValue & $auth->getAuthValue();
    }
    /**
     * 获取角色的权限值
     *
     * @return int
     */
    public function getAuthValue() {
        return $this->authValue;
    }
}
?>

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